/**
 * 判断算一个减法
 */

#include <bits/stdc++.h>
using namespace std;

using llt = long long;
using vi = vector<int>;
using vvi = vector<vi>;

void work(){
    int h, b; cin >> h >> b;
    if(h > b) cout << h - b << endl;
    else cout << 0 << endl;
    return;
}

int main(){
#ifndef ONLINE_JUDGE
    freopen("z.txt", "r", stdin);
#endif
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);	
    int nofkase = 1;
    // cin >> nofkase;
    while(nofkase--) work();
	return 0;
}